Transportation costs associated with an aqueous diluent portion of a formulated aqueous product can be a significant part of the cost of aqueous liquid products. Products, such as sanitizing or cleaning solutions, when used in large amounts can be expensive to use due to transportation costs associated with the aqueous portion. For this reason, many commodity liquid products are shipped from the manufacturer as an aqueous concentrate, an aqueous alcoholic concentrate, or as a viscous concentrate to be diluted in a dispenser with an aqueous diluent at the use locus or site. For example, liquid detergents and cleaning solutions used in hospitality locations, institutional or industrial installations such as hotels, hospitals, restaurants, and the like are often shipped as liquid concentrates that are mixed and diluted using a dispensing device at an appropriate ratio to obtain a useful solution.
Concentrates can be diluted in many ways, varying from manually measuring and mixing to utilizing a computer controlled dilution device. One common dilution technique involves utilizing a dispensing device that combines, under mixing conditions, a flow of concentrate and a flow of diluent. The flow of the liquid diluent can be directed through an aspirator such that, as the diluent passes through the aspirator, a negative pressure arises inside the aspirator drawing the liquid concentrate into the aspirator to mix with the liquid diluent. Both U.S. Pat. No. 5,033,649 to Copeland, according to the invention and are presented for exemplary illustration of the invention. et al. and U.S. Pat. No. 4,817,825 to Freese disclose dispensers having aspirators for diluting liquid concentrates to produce liquid products in this general way. Such aspirator-type dispensers have been used for diluting a liquid concentrate of an arbitrary viscosity with a low viscosity liquid diluent to produce a use solution of intermediate or low viscosity, i.e., the viscosity of the product falls between the viscosity of the concentrate and the diluent.
A use solution of high viscosity is often desirable. Increased viscosity can increase clinging ability to surfaces of an inclined or vertical substrate for more effective and prolonged contact. In addition, a high viscosity hand soap is often easier to use and tends to feel better than low viscosity hand soaps. Relatively viscous use solution made by diluting a low viscosity liquid concentrate with water to form a high viscosity dilute product are described in the prior art. For example, see European Publication No. 0 314 232; U.S. Pat. No. 5,057,246 to Bertha et al.; U.S. Pat. No. 5,922,667 to van Baggem et al.; and U.S. Pat. No. 5,922,664 to Lao et al. It was found that the use of cocamide diethanolamine (DEA) provided use solutions with good viscosity; however, DEAs have recently come under criticism and regulation for concerns relating to carcinogenic effects. Hodge et al., U.S. Pat. No. 6,271,187 is provided a good concentrate and dilutable composition, which included DEA. However, the compositions taught in U.S. Pat. No. 6,271,187 did not perform well in hard water conditions. For example, hard water conditions reduce flash foam and injure foam stability. This is further complicated in a typical wash setting, where the foam is exposed to soils which also injure foam stability. Thus, there is a need to develop use solutions with desirable viscosity, flash foam, and foam stability, that are capable of shipping in concentrated forms and dilutable for use solutions that are free of DEAs, including cocamide DEA, and that perform well in hard water.
A dispenser for dispensing a viscous use solution by diluting a less viscous concentrate is described in U.S. Pat. No. 5,816,446 to Steindorf, et al., which is assigned to Ecolab Inc. of Saint Paul, Minn., the assignee of this application.
Many cleaning compositions include a rheology modifying agent in order to provide the desired viscosity. Further, rheology modifiers that act as foaming agents are particularly desirable in order to increase contact time on surfaces to be cleaned. The most widely used rheology modifier/foaming agent is cocamide DEA, or cocamide diethanolamine, a diethanolamide made by reacting a mixture of fatty acids from coconut oils with diethanolamine. The agent may also been known as lauramide diethanolamine, Coco Diethanolamide, coconut oil amide of diethanolamine, Lauramide DEA, Laurie diethanolamide, Lauroyl diethanolamide, and Lauryl diethanolamide.
It is a viscous liquid and the chemical formula is CH3(CH2)nC(═O)N(CH2CH2OH)2, where n can vary depending on the source of fatty acids. Coconut oil contains about 50% of lauric acid, thus the formula of cocamide can be written as CH3(CH2)10CON(CH2CH2OH)2, though the number of carbon atoms in the chains varies. Cocamide DEA has come under criticism lately and is under regulatory pressure to have it removed from products. It is an allergen that can cause contact dermatitis in individuals who are susceptible to skin allergies. More recently, cocamide DEA has been linked to cancer.
The International Agency for Research on Cancer (IARC) lists coconut oil diethanolamine condensate (cocamide DEA) as an IARC Group 2B carcinogen, which identifies this chemical as possibly carcinogenic to humans. In June 2012, the California Office of Environmental Health Hazard Assessment added Cocamide DEA to the California Proposition 65 (1986) list of chemicals known to cause cancer.
Thus, there has been a desire to replace DEA-based cleaners. However, it was found that once DEA-based rheology modifiers were created to have sufficient viscosity, the formulas failed to provide foam at the desired volume and stability in hard water.
Accordingly it is an object herein to provide cleaning compositions with a combination of components that can be used as a replacement for cocamide DEA while still providing adequate foaming properties.
A further object is to provide cleaning compositions that have adequate foaming properties in hard water.
Still a further object is to provide cleaning compositions that have adequate flash foam and foam stability in hard water.
It is yet another object of the invention to provide cleaning compositions that are safe, environmentally friendly and economically feasible.
Other objects, aspects and advantages of this invention will be apparent to one skilled in the art in view of the following disclosure, the drawings, and the appended claims.